Devotio and Battlefield suicide

In 295 BCE, during the Third Samnite War, the Roman Republic faced a formidable army of Senonian Gauls and Samnites outside of the Umbrian town of Sentinum. The Roman army was commanded by both of the year's consuls, Publius Decius Mus and Quintus Fabius Rullianus. Historians view Sentinum, a crushing Roman victory, as one of the pivotal battles in ancient history, a battle that made the Roman unification of the Italian peninsula a possibility.

Decius' father, who went by the same name, had already performed devotio at the Battle of Veseris in 340 BCE. Devotio was a rare custom, used only as as last resort by ancient Italian generals. The commander would make a vow to Jupiter, Janus, Mars, Bellona, and the gods of the underworld, offering both himself and the enemy soldiers as sacrifices, before advancing to actively seek death in battle.

This is what Decius Mus the Younger did at Sentinum. According to Livy's dramatic account, Decius proclaimed: I will drive before me fear and panic, blood and carnage. The wrath of the heavenly gods and the infernal gods will curse the standards, weapons, and armor of the enemy, and in the same place as I die witness the destruction of the Gauls and Samnites!

He proceeded to lead a cavalry charge against the enemy's right flank, composed of Senones, and was promptly killed. Supposedly, his colleague and the other Roman generals rode down the crumbling Roman lines, shouting that Decius had performed devotio, and this was sufficient to rally the legions. The Senones and Samnites were utterly crushed, and Rome had secured her victory in the Third and final Samnite War.

Performing devotio was apparently something of a family tradition in this branch of the Decii gens; a third P. Decius Mus supposedly led a similar suicide charge at Ausculum, against Pyrrhus of Epirus.

Devotio was nominally the reserve of army commanders; however, there were cases of lesser-ranking Roman soldiers volunteering themselves for what were effectively religiously motivated suicide missions. One of the last and best examples of such a heroic sacrifice was Crastinus, a veteran centurion of Julius Caesar's famous 10th Legion.

Crastinus had presumably seen decorated service in the Gaulish War, and he remained loyal to his general during the subsequent Civil War. On the eve of the Battle of Pharsalus in 48 BCE, he approached Caesar with 120 fellow veterans of the 10th, telling him 'I will do things today, imperator, that you will thank me for, whether I live or die.'

The volunteers were placed on the extreme right flank of Caesar's army, opposite to the legionary veterans of Pompey's left. Crastinus and his men inflicted heavy losses on the Pompeians, before the old centurion himself was killed with a sword thrust into his mouth and out the back of his head. It was a miserable death, but it won him an immortality few other common fighting men of his era ever tasted - Caesar honored him with posthumous decorations and a monument on the battlefield.